Differential Troubles

[Tazman6789]

I own an RC10GT and i took it out for the first time this year and somethin in either the differential or the gears is making this weird grinding noise whenever i pick up the truck not running and just spin the wheels....and when i spin the rear left tire the other tire dosnt spin but when i spin the rear right it spins the other tire the same way...whats wrong with my truck is it the differential or somethin bigger?

 

[Candyman]

So...when you spin the left rear, the right rear doesn't spin? Does the spur gear spin when you do that? But when you spin the right rear, the left spins the same way? Again, when you do that, is the spur gear spinning? In order to see if the diff is bad, you have to hold the spur so it doesn't turn. My hunch is that there's something bad in the right rear. I would check the right rear hub bearings first. Then I would pull the tranny and check the tranny and diff gears..

 

[Tazman6789]

When i hold the spur gear the differential works like it should.....when i just free spin the wheels the spur gear does spin what does this mean?